Semiconductor devices include, among others, light emitting diodes, photo diodes, laser devices, quantum well, superlattice and graded-band-gap devices. These devices, of which lasers are perhaps the best known, generally have a fixed spectral response, that is, emission wavelength, absorption edge, etc. Their use in many fields such as molecular spectroscopy, atmospheric absorption, spectroscopy for pollution detection, heterodyne detection of microwave emissions, laser isotope separation and frequency modulation in optical communications could be expanded greatly if such devices could be readily electrically tunable. It is known that dynamic single mode lasers can be tuned over a restricted wavelength range by adjusting their temperatures. It has been known for many years that certain semiconductor devices can be tuned by applying pressure to the semiconductors but because of the extremely high pressures required no satisfactory devices embodying that principle have hitherto been produced.